Add raw formatter for direct []byte data

As mentioned in the previous commit, some API endpoints return non-JSON
data. We get as far as fetching this data (via client.Logical().Read),
but parsing it as an api.Secret fails (as in this case, it is non-JSON).
Given that we intend to update `vault read` to support such endpoints,
we'll need a "raw" formatter that accepts []byte-encoded data and simply
writes it to the UI.

Signed-off-by: Alexander Scheel <[email protected]>

command/format.go

@@ -70,6 +70,7 @@ var Formatters = map[string]Formatter{
 	"yaml":   YamlFormatter{},
 	"yml":    YamlFormatter{},
 	"pretty": PrettyFormatter{},
+	"raw":    RawFormatter{},
 }
 
 func Format(ui cli.Ui) string {
@@ -125,6 +126,28 @@ func (j JsonFormatter) Output(ui cli.Ui, secret *api.Secret, data interface{}) e
 	return nil
 }
 
+// An output formatter for raw output of the original request object
+type RawFormatter struct{}
+
+func (r RawFormatter) Format(data interface{}) ([]byte, error) {
+	byte_data, ok := data.([]byte)
+	if !ok {
+		panic("backtrace")
+		return nil, fmt.Errorf("unable to type assert to []byte: %T", data)
+	}
+
+	return byte_data, nil
+}
+
+func (r RawFormatter) Output(ui cli.Ui, secret *api.Secret, data interface{}) error {
+	b, err := r.Format(data)
+	if err != nil {
+		return err
+	}
+	ui.Output(string(b))
+	return nil
+}
+
 // An output formatter for yaml output format of an object
 type YamlFormatter struct{}